I was responding to the OP. I’m not sure what your issue may be. You may want to start a new thread (tagged with server-linux) and describe your problem in detail; this thread is about a PMS issue installed on a Windows host.
Try again with the web browser, this time using a private browsing session (In Cognito, InPrivate, Private Window, et al…). Again, using http://127.0.0.1:32400/web. If you could grab a screenshot of that it may be helpful.
Did you sign in as a different user this time? Your original screenshots from Plex Media Player show your “M” user signed in; this new screenshot shows “T.”
Also, to this point, I’ve assumed this was a completely new setup on a new system. Is that correct?
Same problem here. The old version was streaming this morning, but when I needed to add new media to the library, Plex wanted me to upgrade. Now there is no library, and the server asks me to get a new server…